1. Field of the Invention
The present invention generally relates to a telephone and more particularly, to a party selecting circuit arrangement or specifically a party indicating arrangement built in a telephone which is arranged to protect an owner of the telephone from a mischievous call or an erroneous call.
2. Description of the Prior Art
A telephone is constructed in such a manner that, when a party other than the owner of the telephone makes a call, a call sound generated in correspondence to a call signal from a telephone line is heard to notify the owner that the incoming call is received. In the above-described construction of the telephone, however, it cannot be avoided that the owner of the telephone is always called up even by a mischievous call which is made out of mischief and also an erroneous call which is made in error. It may be extremely unpleasant to the owner of the telephone. Therefore, in order to solve the above-described inconvenience, such an improved telephone has been developed that is arranged to discharge a call sound only when a person acquainted with the secret number of the telephone calls up, as disclosed in the published specification of Japanese Patent Laid-Open Publication Tokkaisho (Unexamined) No. 55-11668 (11668/1980).
In the meantime, it is disadvantageously poor operative and easy to dial a wrong number when the entire number of the telephone should be dialed, another type of a telephone which is equipped with an automatic dialing system that allows one-touch dialing with the use of a memory circuit has become widely popular. This type of the telephone is disclosed in the published specification of Japanese Patent Publication Tokkosho No. 53-30601 (30601/1978).
However, in the above-described telephone which is arranged to distinguish or select a caller party by the utilization of the secret number, the secret number is determined by the owner of the telephone, and therefore it is necessitated that the owner should inform the secret number to particular parties, and at the same time it is insecure that the particular parties may forget the secret number.